Mortise lock

ABSTRACT

A latch bolt is movable in a housing in a first direction into and out of the housing between a retracted an intermediate and an advanced position. A catch is mounted in the housing for shifting movement between a normal rest position and a shifted position in a second direction transverse to the first direction. The catch has a cutout provided with two parts which are spaced in the first direction and abutment which separates the two parts and extends partly across the cutout in the second direction. A connector is provided on the latch bolt movable therewith and has a pin which extends into the cutout, and an engaging portion. A lock cylinder is turnably mounted in the housing and can turn between two positions in one of which it displaces the catch to the shifted position wherein the pin may move past the abutment from one cutout part to the other. An arrangement for moving the latch bolt between the several positions includes a handleoperated member operative to engage the engaging portion and displace the latch bolt to the retracted position, but only when the latch bolt is in its intermediate position or between these two positions.

United States Patent [1 1 Schalm 1 Aug. 12, 1975 1 MORTISE LOCK [75] Inventor: Wolfgang Schalm, Senne, Germany [73} Assignee: Schuco Heinz Schurmann & C0.,

Bielefeld, Germany [22] Filed: Aug. 8, 1973 [21] Appl. No.: 386,739

Primary ExuminerAlbert G. Craig, Jr. Attorney, Agent, or FirmMichael S. Striker 5 7 ABSTRACT A latch bolt is movable in a housing in a first direction into and out of the housing between a retracted an intermediate and an advanced position. A catch is mounted in the housing for shifting movement between a normal rest position and a shifted position in a second direction transverse to the first direction. The catch has a cutout provided with two parts which are spaced in the first direction and abutment which separates the two parts and extends partly across the cutout in the second direction. A connector is provided on the latch bolt movable therewith and has a pin which extends into the cutout, and an engaging portion. A lock cylinder is turnably mounted in the housing and can turn between two positions in one of which it displaces the catch to the shifted position wherein the pin may move past the abutment from one cutout part to the other. An arrangement for moving the latch bolt between the several positions includes a handle-operated member operative to engage the engaging portion and displace the latch bolt to the retracted position, but only when the latch bolt is in its intermediate position or between these two positions.

11 Claims, 10 Drawing Figures PATENTED AUG 1 2 I975 SHEET fig. 1

Fig. 4

Pmm mm 21% Q 898 622 SHEET 2 PATENTED AUB12|975 3,898,822

PATENTED AUG] 2 1915 MORTISE LOCK BACKGROUND OF THE INVENTION The present invention relates generally to a lock, and more particularly to a mortise lock.

Mortise locks are already well known and need not be described in detail here as to their purpose and operation. However, the conventional mortise locks usually require relatively large amounts of space for installation and in many instances are not as reliable against the possibility of tampering, as is desirable.

SUMMARY OF THE INVENTION It is, accordingly, an object of the invention to provide an improved mortise lock which avoids the aforementioned disadvantages.

More particularly, it is an object of the invention to provide a mortise lock which has a latch bolt that at the same time serves as a dead lock bolt.

Another object of the invention is to provide a mortise lock which has small dimensions and, therefore, relatively small space requirements.

In keeping with these objects and with others which will become apparent hereafter including that the latch bolt should travel a large distance between its retracted and its advanced position, one feature of the invention resides in a mortise lock which, briefly stated, comprises a housing, and a latch bolt movable in a first direction out of and into the housing between an advanced and a retracted position. A catch is mounted in the housing for shifting movement between a normal rest and a shifted position, and a second direction transverse to the first direction. The catch has a cutout provided with two parts spaced in the first direction and an abutment which separates the two parts and extends partly across the cutout in the second direction. A connector is provided on the latch bolt, being movable with the same and having a pin extending into the cutout. In addition, the connector has an engaging portion. A lock cylinder is mounted in the housing for turning movement between two positions in one of which it displaces the catch to the shifted position. A handle-operated member is operative to engage the engaging portion and to thereby displace the latch bolt from its advanced to its retracted position, but only when the catch is in the shifted position in which the pin can slide past the abutment from one into the other of the parts of the cutout.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of the novel mortise lock in one embodiment thereof, including a portion of a frame into which the lock is to be installed;

FIG. 2 is a perspective view of a component for use in mounting the lock;

FIG. 3 is a view of FIG. 1, as seen in the direction of the arrow III in that Figure, illustrating a fragment of a further embodiment of the invention;

FIG. 4 is a top-plan of FIG. 3;

FIG. 5 is a side view of the embodiment in FIG. I, with one side wall of the housing removed for clarity;

FIG. 6 is a section taken on line VI-VI of FIG. 5;

FIG. 7 shows the embodiment of FIGS. 1 and 5, in a view similar to FIG. 5 but with the latch bolt in retracted position;

FIG. 8 is a view similar to FIG. 7, but showing the latch bolt in advanced and latched position;

FIG. 9 is a view similar to FIG. 8, but showing only a fragment of the lock, illustrating the latch bolt in an intermediate position; and

FIG. 10 is a perspective view showing several components of the illustrated embodiment of FIGS. 1 and 5-9, in exploded condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing in detail, it will be seen that in the various Figures I have illustrated essentially a single embodiment, with FIGS. 3 and 4 showing a variation of one aspect of the invention. Referring firstly to the embodiment in FIGS. 1, 2 and 5l0, it will be seen that reference numeral 1 identifies a frame or door profile provided with an opening 2 into which the mortise lock is to be inserted. At the upper and lower end of the opening 2 there are mounted insert members 3 which are prevented against rotation and which may, for instance, be made of synthetic plastic material. FIG. 2 shows one such insert member which serves to mount the mortise lock, and it will be seen that these insert members 3 are provided with tapped bores into which the mounting screws are inserted which are extended through bores 5 in the portion 6 of the housing of the mortise lock 7. The insert members 3 have the stepped configuration shown in FIG. 2, the step being identified with reference numeral 8 and being present on three sides as shown, with the height or thickness of the step corresponding to the thickness of the wall of the profile I. A supporting portion 9 engages the outer surface of the profile 1 after the respective member 3 has been installed.

Referring now specifically to FIG. 3 and 4, which show a different manner of mounting the lock, it will be seen that in lieu of the members 3 it is possible to provide at the upper and lower ends of the portion 6 of the lock eccentric members 10 which can be turned from the exterior and which engage the upper and lower inner sides of the opening when they are so turned, thereby mounting the lock in the opening of the frame profile 1. Of course, the mounting arrangements of FIGS. 2 on the one hand and 3 and 4 on the other hand can be combined if desired, for instance at the upper end one of the members 3 could be provided, and at the lower end one of the eccentric members 10, or vice versa.

Returning again to the main embodiment in FIGS. 1 and 5-10, it is pointed out that the housing portion 6 can be of one piece with four wall portions of the lock housing 11, and that the housing with the portion 6 can be configurated as a pressure casting. The remaining wall portion 12, which permits access to the interior of the housing, is configurated as a separable plate, for instance a metallic plate which can be connected with the remainder of the housing 11 by means of screws or the like.

In accordance with the present invention, the latch bolt 13 of the novel mortise lock acts at the same time as the dead lock bolt and is provided with a connector 14 which surrounds it and extends upwardly and downwardly beyond the latch bolt 13. In the illustrated embodiment, the latter is of cylindrical configuration and is turnably accommodated in the connector 14. It should be noted, however, that in operation a turning of the latch bolt 13 is prevented by a spring-loaded pin 15 which engages into a lower arcuate recess 16 of the latch bolt. The pin 15 can, however, be pushed into the connector 14 counter to the action of the spring which biases it, in which case the latch bolt 13 can be turned about its longitudinal axis. The latch bolt is provided with two recesses which are offset through 180 so that by so turning it, the latch bolt can be used either for a right-hand or a left-hand lock, simply by turning it.

In the arresting position of the latch bolt, the pin 15 is disengaged by inserting a rod or similar member through an opening 17 and exerting pressure upon the pin 15 counter to the spring biasing the same.

The lower projecting portion 18 of the connector 14 is provided with a projection 19, which can also be considered a pin, and which extends into a cutout 20 of a catch 21. The catch has a downwardly extending arm 22 which is provided with an opening 23 into which there extends an abutment 24 mounted on the housing of the lock. A restoring spring 26 is located between and bears upon the abutment 24 and the lower delimiting surface of the opening 23. A profiled lock cylinder 27 is arranged below the catch and has a cam 28 which, when the lock cylinder 27 is turned, engages the portion 29 of the catch 21 to displace the latter counter to the force of the restoring spring 26 in the direction towards the latch bolt 13. An abutment 30 extends into the cutout 20 to separate the same into two parts, namely an arresting part 31 and a moving part 32; the abutment 30 extends part way across the cutout 20, as shown.

It will be appreciated that when the catch is moved via the cam 28 of the cylinder 27, in the direction towards the latch bolt 13 when the lock is in the position shown in FIG. 5, that the abutment 30 will permit the pin 19 to move under the biasing action of the spring 33 associated with the latch bolt 13, into the part SI of the cutout. As soon as the cam 28 releases the catch 21, the latter returns under the effect of the restoring spring 26 to the position shown in FIG. 8 in which the abutment 30 engages the pin 19, so that the connector 14 and thereby the latch bolt 13 are prevented from performing any movement longitudinally of the axis of the latch bolt 13.

It is thus clear that in the position shown in FIG. 8, the latch bolt 13 acts as a dead lock bolt. It is also shown in FIG. 8 that the extent to which the latch bolt extends into the cooperating frame portion is very significant, and may, for instance, be 25 mm or even more. Because of this significant extent to which the latch bolt extends into the associated frame portion, it is to all intents and purposes impossible to break open the lock by deforming the material of the frame portion sufficiently to cause disengagement of the latch bolt.

When the latch bolt 13 is to be released, the cylinder 27 is turned from the position of FIG. 8 in clockwise direction, and its cam 28 engages the portion 29 on the one hand, and the part 34 of a T-shaped member 35 on the other hand. The member 35 is slidably mounted in the lower portion 18 of the connector 14, for movement within a limited range of displacement. The forward end of the member 35 is provided with an abutment 36 whereas its rearward end has the portion 35 which constitutes another abutment which engages a spring 37 which is located in a recess of the portion 18. When the cam 28 acts upon the member 35 to displace the same, the pin 19 is moved into the part 32 of the cutout 20 and returned from the position of FIG. 8 into the position of FIG. 5 in which a claw 38, which is actuated by the non-illustrated door handle, can engage with the upper portion 39 of the connector 14, to displace the latch bolt to a position, for instance the end position shown in FIG. 7, in which the door can be opened. As long as the pin 19 is located in the part 32 of the cutout 20, the latch bolt 13 operates as a normal latch bolt and does not act as a dead lock bolt.

The claw 38 is mounted on the member 40 for tumable movement and turns in counterclockwise direction when the handle is turned in clockwise direction. A restoring spring 41 is associated with the claw 38, and in the illustrated embodiment the spring 41 is constructed as a torsion spring. The reversal of direction between the movement of the handle on the one hand and the movement of the claw on the other hand is obtained by a linkage arrangement.

The member 40 is provided with a projection 42 which is abutted by a spring 43 which is mounted in the housing. A cam 44 of the member 40 cooperates with a cam 45 of a member 46 which latter is tumable about an axis 47 which extends parallel to the axis 48 of the member 40. The claw 38 is provided with a projection 47 which cooperates with the member 46. The turning movement of the member 46 is counter to the turning movement of the door handle, so that as a result the movement of the claw 38 is also counter to the movement of the door handle. This linkage arrangement, controlled by the various cooperating cams and projections, provides for the desired direction reversal with the smallest possible space requirement so that the configuration and overall dimension of the lock can be small, and consequently the space requirement for installing the lock can be maintained much smaller than was heretofore possible.

To assure that the connector 14 is reliably guided in the housing, it is possible to provide the housing with a guide track 49 into which a projection 50 of the connector 14 extends to be guided thereby. The catch 21 extends over the entire width of the housing and is in slidable engagement with the opposite housing walls.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the type described above.

While the invention has been illustrated and described as embodied in a mortise lock, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further, analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch slidably mounted in said housing and extending over the entire width thereof into slidable guided, engagement with the width-defining housing walls for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a biasing spring biasing said catch to said rest position; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.

2. A mortise look as defined in claim 1, wherein said catch has a projecting portion provided with an opening; and wherein said spring is located in said opening and bears against said catch and said housing.

3. A mortise lock as defined in claim 1, said housing having a plurality of walls, including one side wall; and wherein all of said walls except for said one side wall are of one piece with one another.

4. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a deadlock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, an engaging portion and another portion, and a T-shaped member which is journalled in said other portion for limited sliding displacement against a biasing member; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.

5. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions, said handle-operated member comprising a claw, a movable component and a linking member pivotally supported by said housing and connecting said claw and said movable component and reversing the motion of the latter when transmitting such motion to the former.

6. A mortise lock as defined in claim 5, said movable component being movable against the force of a biasing member and including a projection, said pivotal linking member being engageable by said projection and movable in a direction opposite to that of said movable component and engaging said claw and moving the same against the force of an additional biasing member.

7. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion, said latch bolt being substantially cyiindrical and being turnably joumalled in said connec .or and having an arcuate recess into which a spring-biased pin extends for controlling the turning movement of said latch bolt; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.

8. A mortise lock as defined in claim 7, said latch bolt having an additional arcuate recess which is offset through relative to the first-mentioned arcuate recess; and wherein said pin is disengageable from one said arcuate recess and engageable with the other.

9. A mortise lock, comprising a housing; a latch bolt movabie in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions; and inserts receivable in a door wherein said lock is to be installed, said inserts having tapped bores into which screws for mounting said lock are threadable so as to mount said lock on said door in said inserts.

10. A mortise lock as defined in claim 9, wherein said inserts have rotation-preventing portions.

11. A mortise lock, comprising a housing; a latch bolt movable in afirst direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions; and turntable eccentric means on said lock for arresting the same in an opening provided in a door wherein said lock is to be installed. 

1. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch slidably mounted in said housing and extending over the entire width thereof into slidable guided, engagement with the width-defining housing walls for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment sepArating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a biasing spring biasing said catch to said rest position; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.
 2. A mortise lock as defined in claim 1, wherein said catch has a projecting portion provided with an opening; and wherein said spring is located in said opening and bears against said catch and said housing.
 3. A mortise lock as defined in claim 1, said housing having a plurality of walls, including one side wall; and wherein all of said walls except for said one side wall are of one piece with one another.
 4. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, an engaging portion and another portion, and a T-shaped member which is journalled in said other portion for limited sliding displacement against a biasing member; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.
 5. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions, said handle-operated member comprising a claw, a movable component and a linking member pivotally supported by said housing and connecting said claw and said movable component and reversing the motion oF the latter when transmitting such motion to the former.
 6. A mortise lock as defined in claim 5, said movable component being movable against the force of a biasing member and including a projection, said pivotal linking member being engageable by said projection and movable in a direction opposite to that of said movable component and engaging said claw and moving the same against the force of an additional biasing member.
 7. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion, said latch bolt being substantially cylindrical and being turnably journalled in said connector and having an arcuate recess into which a spring-biased pin extends for controlling the turning movement of said latch bolt; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; and means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions.
 8. A mortise lock as defined in claim 7, said latch bolt having an additional arcuate recess which is offset through 180* relative to the first-mentioned arcuate recess; and wherein said pin is disengageable from one said arcuate recess and engageable with the other.
 9. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions; and inserts receivable in a door wherein said lock is to be installed, said inserts having tapped bores into which screws for mounting said lock are threadable so as to mount said lock on said door in said inserts.
 10. A mortise lock as defined in claim 9, wherein said inserts have rotation-preventing portions.
 11. A mortise lock, comprising a housing; a latch bolt movable in a first direction out of and into said housing between an advanced dead-lock position, an intermediate latching position and a retracted position; a catch mounted in said housing for shifting movement between a normal rest and a shifted position in a second direction transverse to said first direction and having a cutout provided with a dead-lock part and a latching part, the two parts being spaced in said first direction, and an abutment separating said two parts and extending partly across said cutout in said second direction; a connector on said latch bolt, movable therewith and having a pin extending into said cutout, and an engaging portion; a lock cylinder mounted in said housing for turning movement between two positions in one of which it displaces said catch to said shifted position wherein said pin may move past said abutment from one cutout part to the other; means for moving said latch bolt between the several positions and including a handle-operated member operative to engage said engaging portion and displace said latch bolt to said retracted position, only when said latch bolt is in said intermediate position or inbetween these two positions; and turntable eccentric means on said lock for arresting the same in an opening provided in a door wherein said lock is to be installed. 